Stencil paper



Patented July 4, 1933 UNITED STATES PATENT OFFICE KENNETH CARE, OF OAK PARK, ILLINOIS, ASSIGNOR TO DITTO, INCORPORATED, OF CHICAGO, ILLINOIS, A CORPORATION OF WEST VIRGINIA STENCIL PAPER No Drawing.

This invention relates to improvements in stencil paper and more particularly to stencil paper comprising a base material of loose, open texture, such as for instance, yoshino paper, having a coating of such nature that it may be impressed and cut by a type of type- Writing machine or by a stylus or similar instrumentality.

The invention herein set forth is an improvement in the process and article set forth in the applicants co-pending applications Serial N 0. 138,572, filed September 29th, 1926 forImprovements in stencil paper and Serial No. 355,983, filed April 17th, 1929, for Improvements in stencil sheets.

The present invention like those set forth in the copending applications referred to, employs a base material. a phenol formaldehyde resin characterized as being more flexible than other resins of this general kind, in that the phenol, prior to its reaction with formaldehyde, is reacted with tung oil. This resin is fully described in and constitutes the subject matter of the invention of Patent No.

1,590,097, issued to Byck, on July 22nd. 1926. This resin is particularly adaptable for use in making stencil sheet coatings for the reason that the tung oil imparts a flexibility thereto whereby the resin is partially plasticized to an extent which renders it unnecessary to subsequently incorporate other plasticizing agents in large quantities.

Therefore. the resin may be modified by a suitable shortening agent or agents, which in the present illustration, is preferably aluminum stearat-c. It is then only necessary to add suitable softeners or lubricants in sufficient quantity to bring the mixture to that degree of plasticity where the desired cutting action may be produced.

Among other agents, certain oils containing fatty acids, such as neatsfoot oil, peanut oil or corn oil, have been found to serve well as softeners in coatings employing the phenol resin referred to as a base material.

Coatings so made, possess the property of giving a very clean but relatively narrow cut when struck by the type of a typewriter or impressed with a stylus, which in many instances,'is quite satisfactory, but in other instances, where it is desired to produce a 1 broader cut, it has been found that the addition of a wax, such asparafiin or cerasin or other wax-llke materials such as stearicacid,

Application filed May 7, 1930. Serial No. 450,601.

japan wax, tallow and like substances, give this property.

, It has also been found that the particular base ingredient here employed, namely the phenol formaldehyde resin exhibits the property of repelling fatty acids, which are present in the softening oils employed with the result that small amounts of fatty acids are deposited out of the coating composition onto the surface of the sheet producing an undesirable White frost or bloom thereon. It is found that the presence of this frost or bloom does not impair the quality of the stencil in any way, but that it merely detracts from the appearance thereof and consequently to some degree, diminishes its commercial value.

In view of the above behavior, the applicant has discovered a substance, the presence of which in the composition, acts in the capacity of the wax or Wax-like material above described, and further acts to hold the fatty acids in the composition with the consequent elimination of the frost or bloom referred to.

It is the object of this invention therefore,

. to produce a stencil sheet of improved qualities employing a phenol formaldehyde resin as a base material, and oils as softening agents, characterized by the elimination of any tendency to deposit afrost or bloom on its surface.

The substance which has proven most desirable for this use is chlorinated naphthalene, which is otherwise known on the market as halowax, in any of its solid or semi-solid forms.

It has also been found that a wax produced on the market by the General Dyestuffs Corporation, which is in the nature of a synthetic carnauba wax, may be used with good results. The applicant has endeavored to ascertain the exact chemical-nature of thissynthetic wax, but finds that its chemical composition is unknown to the General Dyestuffs Corporation and that there is no other way to identify it, other than by the titles E wax and O Wax, given to it by said corporation. The E wax and O wax vary slightly in hardness, but are otherwise quite similar and are both found to serve well in practice in the applicants invention.

As above pointed out, except for the undesirable frost or bloom on the surface of the sheet, paraflin or cerasin waxes may be used. It is therefore contemplated in the present invention, that chlorinated naphtha- Resin varnish (45% of the resin in solulene may be used alone, or it may be used with a quantity of cerasin wax or any other waxlike materials suitable for this purpose, or in fact, anycombination of these, which will give the desired softening or lubricating properties and yet prevent thefrosting or blooming.

Furthermore, it may be mentioned that the waxes or wax-like substances referred to give the desirable property of distendingthe coating composition; that is to say, of giving the coating the desired displaceable mass, but some possess this property to a greater degree than others.

By way of illustration, parafiin wax is first, cerasin next, and chlorinated naphthalene is last, in order, insofar as this distending property is concerned. On the other hand, the chlorinated naphthalene and the synthetic carnauba waxes referred to are those which excel in the property of retaining the fatty acids in the composition and although parafiin wax has this property. to a slight extent, the present invention contemplates incorporating at least a part of one or both of the chlorinated naphthalene or the synthetic carnauba waxes in order to eliminate the bloom.

It therefore can be appreciated, in view of the problem involved, that different proportions of any combination of the substances may be used, depending upon the properties desired for the final stencil sheet.

With this understanding of the invention, it will be obvious that some latitude should be allowed in compounding any particular stencil sheet, but by way of illustration, for the purposes of this application, one preferred form will be given as follows 2- A proper solvent is first selected which will serve to dissolve or produce a homogeneous mixture with the various ingredients entering into the coating composition. The quan-' tity of solvent will vary in different instances, but should be selected to produce a final solution of a consistency suitable for the dipping or otherwise coating stencil sheet paper.

Suitable solvents for this use are, a mixture of toluol and alcohol, or toluol and ethylenedichloride, although the invention is not to be limited to these. Two parts of aluminum stearate are added to the solvent, and theref w i Parts tion) Chlorinated naphthalene 10 Corn oil 13 Victoria blue base, are added A In the above formula, naphthalene in solid crystalline form should be used, the exact kind of which is identified on the market, as No. 1012.

With the coating composition so formed,

the chlorinated the sheets of yoshino or like paper may be dipped or otherwise coated in the manner now well known in the art and thereafter the sheets are baked in a suitable oven to convert the resin into its final insoluble and infusible form,.all as set forth in applicants co-pending applications referred to.

The above formula may be varied by reducing the quantity of chlorinated naphthalene and adding a quantity of paraffin or cerasin, or both, in amount such that the entire combination will produce the desired softening and yet will not permit the frosting or blooming to take place.

The following formulas which may be made up in the same way, are preferred examples for use with the synthetic canaba waxes In the above formula, cerasin may be substituted for the parafin.

Parts Resin varnish 16 Aluminum stearat-e 2 Synthetic carnauba wax (13 Wax) 1 Chlorinated naphthalene No. 1012 4 Corn oil 9 Sperm oil 1 Victoria blue base In the next above formula, sperm oil may be omitted, 'in which event, the corn oil should be increased to 10 or 11 parts.

With each of the above formulas, improved stencil sheet is provided, employing the plasticized synthetic resin referred to as a base material, together with oils containing fatty acids as softening agents, which will not be subject to the undesirable frosting or blooming.

he stencil sheet is also one which will give relatively broad, but clearly defined characters when cut with the type of the typewriter or stylus.

It should be noted that this invention involves a distinct principle and it teaches a method for overcoming certain difiiculties heretofore encountered and it further sets out, with some degree of latitude, the method 6 of practicing this invention, while pointing to the results which may be expected from varying the possible formulas.

This invention therefore, should not be construed as limited to the particular formulas herein given, but should extend to fully protect the under-lying principles of this teaching.

The scope of the invention may be determined by reference to the appended claims a highly which should be construed in the light of the present teaching and an appreciation of the principles exhibited in the disclosed illustration.

I claim:

1. A stencil sheet coating composition containing the following substances in substantially the proportions specified:

' arts Aluminum steara-te solution) phenol formaldehyde resin 16 Chlorinated naphthalene 14 Corn oil 13 an oil or oils containing fatty' resin capable upon further heat treatment of being rendered substantially insoluble and infusible; corn oil; and chlorinated naphthalene.

5. A stencil sheet comprising -a'soluble, flexible phenol formaldehyde resin capable upon further heat treatment of being rendered substantially insoluble and infusible; an oil or oils con-- taining thalene.

6. A stencil sheet of the character described composed of a backing sheet of loose fatty acid; and chlorinated naphopen fibrous texture, and a coating thereon' comprising a substantially insoluble and infusible phenol formaldehyde resin, an oil or oils containing fatty acid and chlorinated naphthalene.

7 A stencil sheet of the character described composed of a backing sheet or loose open fibrous texture and a coating thereon comprising a substantially insoluble and infusible phenol formaldehyde resin, an oil or oils containing fatty acid, aluminum stearate and'chlorinated naphthalene.

Signed at Chicago, Illinois, this 5th day of May, 1930. p

' KENNETH W. CARR.

coating composition 

